Leadership, said New Jersey Gov. Chris Christie in his press conference Tuesday announcing he wouldn’t run for president, is something you can’t be taught or learn. “Leadership today in America has to be about doing the big things and being courageous.”

No one doubts that Christie has shown this kind of leadership in New Jersey. Call him bombastic, call him confrontational, but don’t call him wobbly. He leads, and even with a Democratic-majority legislature, the state is moving in his direction.

Things are different nationally. On the day before Christie spoke in Trenton, the Obama White House officially delivered the Free Trade Agreements with South Korea, Colombia and Panama to Congress for approval. That was the 986th day that Barack Obama has been president.

He could’ve sent them 985 days earlier; negotiations were completed in 2006 and 2007. Or, if he were concerned they’d be deep-sixed when his fellow Democrats controlled Congress, he could’ve sent them 274 days earlier, when the GOP took over the House.

To be sure, they are opposed by many labor leaders and congressional Democrats. There is a nostalgia among many union and party old-timers for the days, more than 30 years ago, when the auto and steel workers’ unions had nearly 2 million members.

Now each has less than half a million. But the old-timers seem to feel that somehow those olden days can be brought back if they oppose free-trade agreements.

Any responsible president must take a different view. The free-trade pacts in question dismantle mostly barriers to US exporters. Barriers to imports are already low or nonexistent.

These are serious markets: South Korea has the 11th or 12th largest economy in the world; Colombia is the second largest Spanish-speaking country; Panama has had vigorous economic growth and is widening the Panama Canal to allow Pacific container ships into Gulf and Atlantic ports.

Democratic presidents used to lead on trade. John Kennedy’s major domestic initiative in his first two years was a trade expansion act. Most Democrats voted for it, and most Republicans against.

Bill Clinton strongly backed the North American Free Trade Agreement — an initiative of Mexican border-state politicians like Ronald Reagan, George H.W. Bush and Lloyd Bentsen — and pushed it through a Democratic Congress.

Obama chose a different course. He has held back on free-trade accords and put pressure on the other treaty partners to make concessions. This propitiated his union allies and their sympathizers for a time.

But his State of the Union message call for doubling US exports made it obvious that he would have to get Congress to approve the free-trade deals. How can you double exports if you refuse to advance measures that would open up markets to them?

Now the unions and many Democrats are angry at him for not continuing to obstruct the free trade agreements. In the meantime, South Korea has been signing free trade agreements with the likes of Chile and the European Union. That gives European exporters a head start over Americans.

So Obama has left his allies angry and his critics unmollified — the opposite of strong leadership.

You can see a similar story unfolding on the approval of the Keystone pipeline. This is a privately financed pipeline to transport oil from the tar sands of Alberta, Canada, to oil-marketing facilities at Cushing, Okla.

Like the free-trade deals, it’s a no-brainer: We get oil from friendly nearby Canada instead of the unstable distant Mideast. Some 20,000 jobs are created without a government dime.

But environmental groups are griping about Canada’s drilling methods and possible pipeline accidents, and the State Department, despite a clean environmental bill of health, has been stalling on providing the necessary approval.

But it surely will. The enviros will be cross; the jobs that might help re-elect Obama won’t be created until after the election.

Christie has shown that confrontational leadership can get results and produce more admirers than detractors. Obama has shown that lack of leadership leaves pretty much everyone dissatisfied.